Structural Traps and Hydrocarbon Resources of the Papuan Basin: An Overview

Abstract

Papua New Guinea has become one of the world’s most exciting exploration regions, with significant hydrocarbon potential. The key geological element that controls hydrocarbon accumulation evolved over the initial Permian−Triassic basement rifting and post-sedimentation inversion folding and faulting largely due to the S−SW propagation of the Pacific plate toward the stable Australian craton. In this study we categorize the larger Papuan basin into four main geological areas based on hydrocarbon exploration, discovery, development and production. Recent seismic data acquired by Searcher Seismic over the Gulf of Papua (GoP) has revealed exciting new structural potential for hydrocarbon accumulation. High quality seismic data revealed a more comprehensive play identification in deep to shallow-waters of GoP. Basement rifting structural plays with post-rift carbonate and turbidite siliciclastic deposition are the key reservoir plays. Pasca, Pandora and Uramu gasfield discoveries were made on Miocene reefal carbonate build-ups on faulted basement highs. The carbonate and siliciclastic plays are estimated to have a combine resource of up to 306MMboe–gas/condensate. The Aure fold thrust belt (AFTB) has a complex structural zone where regional thrust change orientation from NW−SE to N−S. Onset of Tertiary transpressional deformation of the AFTB cross-cuts older structures developed by arc-continental collision in the Papuan fold thrust belt (PFTB). Shallow thrust detachment faults in the upper Ieru formation were reactivated by basement faults during the persistence compressive tectonics in Pliocene. The thrusted platform slope and reefal Miocene carbonates become the primary reservoir plays in the region. The region is estimated to have a potential resource of 2,225MMboe–gas/condensate. The Papuan foreland basin structures are fairly very simple because extensional faulting of Paleozoic granitic basement during Triassic−Early Jurassic has created low relief faulting anticlinal structural closures. Sediment draping over structural highs are also potential plays in the foreland. Reactivation of basement faults during the Late Cretaceous eastern Australia extension has played significant role in configuration of the structural plays. Late Jurassic–Early Cretaceous marine siliciclastic reservoirs are the primary play targets. Potential resources for the foreland region is estimated at 582MMboe–gas/condensate. The PFTB structural play styles were influenced by extension of basement in the Triassic−Jurassic and compression in Late Miocene. Seismic imaging and well dataset imply changes in structural styles across the PFTB. Thin-skinned southwest directed emergent thrust faults and ramp anticlines are associated with the Kutubu producing fields. Toward the northwest in the Muller range structural styles are associated with basement involvement and northeast directed fold and thrust structures. Large-scale structural changes and associated structural complexities reflect on the structural controls on the deformation and the influence on both the trapping style and distribution of hydrocarbon within the PFTB. The overall estimated resources (produced, undeveloped and yet to find) for the region is 2,867MMboe–oil/gas/condensate.

AAPG Datapages/Search and Discovery Article #90371 © 2020 AAPG Asia Pacific Region, The 1st AAPG/EAGE PNG Geosciences Conference, PNG’s Oil and Gas Industry: Maturing Through Exploration and Production, Port Moresby, Papua New Guinea, February 25-27, 2020